Such thermostatic valve includes internally, a valve actuator responsive to the pressure and/or temperature consisting of one or more expansible metallic cells, bellows or the like with the actuator supporting for movement a valve closure movable towards and away from a valve seat within a valve outer body or casing defining the outlet port of the valve.
The assembled valve structure including the outer body or casing carrying the valve seat is customarily installed as a permanent part of the heating system. While some parts may last indefinitely, the actuator, the valve disc and the seat are subject to deterioration so that replacement or repair of one or more of these parts at intervals is normally necessary. Typically, the outer body or casing is closed off at the top by a threaded cover permitting access to the valve body interior so that the actuating element may be removed from the valve casing for repair or replacement. One of the problems in replacing or repairing the actuating element is to provide or effect accurate adjustment of the reassembled parts or to permit substitution or replacement of parts which have deteriorated or which have been destroyed so that the replacement parts or repair parts can operate under the same temperature and pressure parameters, as those initially installed.
U.S. Pat. No. 1,911,230 issued May 30, 1933 is directed to a thermostatic valve of that type in which the parts of the valve, commonly subject to rapid wear or deterioration, constitute a unitary assembly which may be accurately calibrated by empirical methods, is capable of installation in conventional steam trap casings by dropping it freely into the valve body or casing after removal of the cover where, the assembled unit is held in proper position.
While such internal assembly has permitted the thermostatic valve to operate satisfactory, when unit parts replace those are worn or inoperative and while the unit parts permit precalibration prior to assembly, the replacement unit as evidence by U.S. Pat. No. 1,911,230, is characterized by a hollow cylindrical cage formed totally or principally of sheet metal components and utilizes a coil spring compressed between the threaded cover and the cage for maintaining the unit in position. Such arrangement often fails to maintain the desired relationship, or fails to insure a seal between the replacement part and the valve casing and cover and the unit components are relatively complex and therefore costly.
It is a primary object of the present invention, therefore, to provide an improved thermostatic valve employing a trap repair cartridge which is has an annular intermediate valve body of cast metal, is threaded at one end to the valve casing and at the opposite end to the cover, which is of simplified construction, which in turn threadably supports the valve trap disc, coaxially of the valve seat, which employs a simple adaptor post to maintain proper positioning between the valve trap disc and the cover, which permits reuse of the cover, and which constitutes a simple and low cost assembly.